1. Field
The present embodiments relate to a magnetic recording head including main magnetic pole layer, return path layer, and coil layer.
2. Related Art
FIG. 6 is a perpendicular magnetic recording cross-sectional view of a configuration of a magnetic recording head in the related art disclosed in JP-A-10-269533.
A known magnetic recording head H500 shown in FIG. 6 is formed at a trailing portion (the Z1 direction in the drawing) of a nonmagnetic insulating layer 612 formed on a substrate. A configuration including a playback head for reading is disclosed in JP-A-10-269533, but the playback head is not shown in FIG. 6 to help easy understanding of the following description.
As shown in FIG. 6, in the magnetic recording head H500 in the related art, a main magnetic pole layer 524 is formed on a substrate (not shown) and a yoke layer 536 connected with the main magnetic pole layer 524 is formed.
A return path layer 521 is formed over the yoke layer 536 (in the Z1 direction). A connecting portion 521a is formed downward in the return path layer 521 (in the Z 2  direction) and magnetically connected with the yoke layer 536 at the inside of the yoke layer 536 (height direction, in the Y 2 direction).
As shown in FIG. 6, in the magnetic recording head H500, a coil layer 527 wound around the connecting portion 521a is formed between the main magnetic pole layer 524 and the return path layer 521. An insulating layer 533 is formed around the coil layer 527. FIG. 7 is a partial plan view of the magnetic recording head shown in FIG. 6.
FIG. 8 is a partial cross-sectional view of a configuration of a magnetic recording head in the related art disclosed in JP-A-2002-197613 (U.S. Pub. No. 2002/0078553). FIG. 9 is a partial plan view of the magnetic recording head shown in FIG. 8.
The magnetic recording head H600 shown in FIG. 8 is formed at a trailing portion (Z1 direction) of a nonmagnetic insulation layer 612 formed on a slider (not shown). A configuration including a reading portion is disclosed in JP-A-2002-197613 (U.S. Pub. No. 2002/0078553), but the reading portion is not shown in the drawing to help an easy understanding of the following description.
In the magnetic recording head H600, the return path layer 621 is formed by plating a strong magnetic material. The nonmagnetic insulating layer 612 is formed under (Z2 direction) and around the return path layer 621.
As shown in FIG. 8, a connecting layer 625 is formed on the surface 621a of the return path layer 621 in the inner portion than a facing surface H1a (height direction, Y2 direction).
In the surroundings of the connecting portion 625, a nonmagnetic insulating layer 626 is formed on the surfaces 621a and 612a of the return path layer and the nonmagnetic insulating layer 612, and a coil layer 627 formed of an electric conductive material is formed on the nonmagnetic insulating layer 626.
The coil layer 627 is coated with an insulating layer 632 and further covered with an insulating layer 633.
In the magnetic recording head H600 a main magnetic pole layer 624 is formed on the insulating layer 633 through the plated ground layer 624b. 
A yoke layer 636 is formed on the insulating layer 633 through an inorganic insulating layer 635 and plated on the plated ground layer 636d. The rear portion 624 of the main magnetic pole layer 624 and a front portion 636b of the yoke layer 636 are magnetically connected and the rear portion 636c of the yoke layer 636 is magnetically connected with the upper surface 625a of the connecting layer 625.
The magnetic recording head H600 is coated with a protecting layer 613 formed of an inorganic-nonmagnetic insulating material or the like.
FIG. 9 is a partial plan view of the magnetic recording head H600 as described above. However, FIG. 9 illustrates only the main magnetic pole layer 624 and yoke layer 636.
As shown in FIG. 9, in the magnetic recording head H600, a rear portion 624c formed at the inside in the height direction (Y2 direction) from a base 624d formed at the main magnetic pole layer 624 gradually increases in width and overlaps the yoke layer 636.
As shown in FIG. 9, the magnetic recording head H600 is configured such that the front end 636a is disposed closer to the facing surface H1a than the base 624d formed in the main magnetic pole layer 624 and the base 624d is covered with the yoke layer 636.
In the magnetic recording head H500 disclosed in JP-A-10-269533, the plane shapes of the main magnetic pole layer 524 and yoke layer 536 are not clearly described. However, the main magnetic pole layer 524, as shown in FIG. 7, is generally configured such that the rear portion 524 formed inwardly in the height direction (Y2 direction) from the base 524b formed in the main magnetic pole layer 524 gradually increases in width and the rear portion 524c overlaps the yoke layer 636.
In JP-A-10-269533, for example, the magnetic recording head shown in FIG. 7, the positional relationship of the front end 536a of the yoke layer 536 and the base 524b of the main magnetic pole layer 524 are unclear. When the base 524d of the main magnetic pole layer 524 is disposed closer to the facing surface H1a than the front end 536a of the yoke layer 536 to improve magnetic recording efficiency by concentrating the recording field on the front end (when the yoke layer 536 is disposed as indicated with a solid line), leakage magnetic flux φm1 is generated due to magnetic saturation at the base 524b and the leakage magnetic flux φm1 is applied to the recording medium M.
When the front end 536a of the yoke layer 536 is disposed closer to the facing surface H1a than the base 524b and the base 524b is spaced from the facing surface H1a at a sufficient distance, the leakage magnetic flux φm1 can not be applied from the base to the recording medium M. However, in the magnetic recording head H500, as shown in FIG. 6, the front end 536a of the yoke layer 536 is not covered with the return path layer 521 and the magnetic flux φm2 from the yoke layer 536 is applied to the recording medium M, because the return path layer 521 extends in a line in the height direction (Y1-Y2 direction).
In other words, when the base 524b is disposed closer to the facing surface H1a than the front end 536a of the yoke layer 536 to improve recording efficiency, a recording signal in an approximate track on the recording medium M is removed by the leakage magnetic flux φm1 from the base 524b. 
Alternatively, when the front end 536a of the yoke layer 536 is disposed closer to the facing surface H1a than the base 524b to prevent the leakage magnetic flux φm1 from the base 524b being applied to the recoding medium M and to effectively induce recording magnetic field at the main magnetic pole layer 524 by the yoke layer 536 (when the yoke layer 536 is disposed as indicated with a dashed line), the leakage magnetic flux φm2 from the yoke layer 536 is applied to the recording medium M because the front end 536a of the yoke layer 536 is not covered with the return path layer 521.
For example, the maintenance of recording efficiency by concentrating magnetic flux of recording magnetic field and effect of prevention of leakage magnetic field is contrary to each other, so that they were not achieved at the same time in the known magnetic recording head H500 shown in FIG. 6.
In the configuration disclosed in JP-A-2002-197613 (U.S. Pub. No. 2002/0078553), for example, in the magnetic recording head H600 shown in FIG. 8, the front end 636a of the yoke layer 636 is disposed closer to the facing surface H1a than the base 624d, as shown in FIG. 9, but the yoke layer 636 is formed at the opposite side (Z1 direction) to the return path layer 621 with respect to the main magnetic pole layer 624, as shown in FIG. 8. Therefore, the leakage magnetic flux φm2 from the yoke layer 636 is easily applied to the recording medium. Accordingly, a recording signal recorded in an approximate track on the recording medium M is removed and recording efficiency cannot be improved.